US CDC reports 10,000 breakthrough infections after full vaccination: showing success of vaccine programme
1 June 2021. Related: COVID-19: vaccine research, COVID-19.
Simon Collins, HIV i-Base
On 25 May 2021, the latest issue of MMWR included a review of breakthrough cases of COVID-19 reported up to the ends of April.
The 10,262 cases are a tiny percentage (0.01%) of the more than 100 million people fully vaccinated at the time of the analysis, and were expected given that vaccines are not 100% effective. They were largely mild infections, but not always, and perhaps half were linked to new variants.
The 10,262 cases are a tiny percentage (0.01%) of the more than 100 million people fully vaccinated at the time of the analysis, and were expected given that vaccines are not 100% effective. They were largely mild infections, but not always, and perhaps half were linked to new variants.
Breakthrough infections were defined as occurring more than 14 days after receiving the second dose of an authorised vaccine, confirmed by RNA testing.
Median age was 58 (IQR: 40 to 74) and 63% were women. Approximately 27% were asymptomatic. 995 were hospitalised (not always related to COVID-19). Although 160 people died, this is dramatically lower than without vaccination where the US has reported more than 30 million cases and 600,000 deaths.
The median age of people who died was 82 (IQR: 71 to 89), including 28 (18%) unrelated to COVID-19.
Genomic sequencing was only available for 555 (5%) of cases, of which almost two-thirds (n=356, 64%) were variants of concern, including B.1.1.7 (199; 56%), B.1.429 (88; 25%), B.1.427 (28; 8%), P.1 (28; 8%), and B.1.351 (13; 4%).
The surveillance programme depends on passive reporting so the results are likely an underestimate. Future reports will also only focus on people who are hospitalised.
More than 130 million adults in the US (~40% of adults) have now had two doses.
Reference
CDC. COVID-19 vaccine breakthrough infections reported to CDC — United States, January 1–April 30, 2021. MMWR Morb Mortal Wkly Rep. ePub. 2021 (70). DOI: 10.15585/mmwr.mm7021e3. (25 May 2021).
https://www.cdc.gov/mmwr/volumes/70/wr/mm7021e3.htm
This report was first posted on 26 May 2021.